A new study from the University of Nottingham has calculated that there could be more than 30 intelligent communicating civilizations in our galaxy, based on the idea that intelligent life develops similarly across the universe.
Published today in the Astrophysical Journal, researchers believe there may be 36 intelligent civilizations throughout our galaxy, building on previous estimates that placed that figure on a rather broad scale between zero and billions.
Christopher Conselice, who led the research, explained that “There should be at least a few dozen active civilizations in our Galaxy under the assumption that it takes 5 billion years for intelligent life to form on other planets, as on Earth.”
The calculation, what the researchers have dubbed Astrobiological Copernican Limit, aims to look at evolution on a cosmic scale rather than an Earth-centric one, and gets its namesake from Nicolaus Copernicus, the astronomer who first formulated a model of the universe that placed the Sun rather than Earth at its center.
First author of the study, Tom Westby, explained how the Astrobiological Copernican Limit simplified previous estimations which relied on “making guesses of values relating to life, whereby opinions about such matters vary quite substantially.”
The more objective methodology used here is based on two central limits. The first is that intelligent life forms in less than 5 billion years, the second that it arrives after 5 billion years (on Earth, we formed a communicating civilisation after 4.5 billion years).
The first author of the study also explains that if we take these limits, then “In the strong criteria, whereby a metal content equal to that of the Sun is needed (the Sun is relatively speaking quite metal rich), we calculate that there should be around 36 active civilizations in our Galaxy.”
The number of civilizations depends largely on how long they are able to send out signals of their existence into space (radio signals, television, satellites, etc.) On our planet, we currently sit at around the 100-year mark, which would suggest that there are at least another 36 civilizations existing concurrently throughout the galaxy.
The problem of course being that the average distance between these civilizations would be tens of thousands of light years, making it nearly impossible for any of one of them to communicate with the other.
The new model suggests that, in all probability, there should be at least 30 or more civilizations out there similar to ours. However, if there are not, it raises some serious questions about the longevity of our own.
That is because, if it turns out that intelligent life is common, then it should be able to exist for more than a few hundred years. However, if it is not, it would suggest that intelligent life has a lifespan, one which we still have yet to reach.
As Conselice himself says, “by searching for extraterrestrial intelligent life – even if we find nothing – we are discovering our own future and fate.”
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